Using a cocktail shaker, add ice and shake all ingredients except for the soda.
Pour into a Collins glass
Top with soda
Place optional garnish dehydrated grapefruit wheel in glass. Or garnish with a lime wedge.
To create a dehydrated grapefruit wheel, use a mandolin or knife to cut a wheel of grapefruit, and grill on a gas grill over a high flame for no more than one minute on each side. You’ll want to see the grill marks, but not cook the fruit. Cool.To make Simple Syrup. 1/2 cup granulated sugar and 1/2 cup water. Add the sugar and water to a small saucepan over medium heat. Stir until sugar is dissolved. Strain into a jar and seal tightly with a lid. Simple Syrup will keep in the refrigerator for one month.